Even as international efforts to address climate change have gathered momentum, emissions of heat-trapping gasses have risen, reaching a new peak last year. The next major opportunity to reverse the trend will be the United Nations’ Climate Action Summit in New York this coming September. But a necessary element that could break the deadlock—U.S. leadership—will be absent.
Back in 2016, at the end of U.S. President Barack Obama’s tenure, the United States formally joined the Paris agreement, which he believed was the “most ambitious climate change agreement in history.” By signing on, Obama argued, the United States had become a global leader in the fight against climate change. He was right—at that time, the United States was on track to cut carbon emissions by up to 26 percent below 2005 levels by 2025, in line with the objective it had set under the agreement.
But that moment has passed. In 2018, emissions growth resumed as the Trump administration rolled back the Obama-era environmental protections. This wasn’t the first time such a thing had happened. In fact, the cycle is relatively well established.
Over the past three decades, the United States has made four international commitments to reduce its emissions: at Rio in 1992, at Kyoto in 1997, at Copenhagen in 2009, and at Paris in 2015. Yet ambitious agreements to reduce emissions have in each case been followed by steadily increasing emissions as international promises have failed to turn into domestic legislation.
As a result, the United States has emitted around 20 billion tons of carbon dioxide more than it has promised to since 1992. By 2025, it will likely overshoot the target by another 5 billion tons. On its own, the 25-billion-ton surplus amounts to more than total Chinese, Indian, and European Union emissions last year. It will cause more than a $1 trillion in damage to the global economy over the coming years, based on an estimate produced by the federal government in 2016 that each ton of emissions causes about $42 of economic damage to the global economy.
To explain away all the excess carbon, President Donald Trump likes to claim that agreements were unreasonable, representing “draconian financial and economic burdens” on the United States. But in reality, U.S. negotiators have been highly successful in resisting unrealistic commitments over the past three decades. For example, the Kyoto target the United States agreed to was far less ambitious than what the other parties wanted. The agreement also allowed for market-based mechanisms, which the United States had wanted to ensure that compliance would be cost-effective.
Further, experts find no major technical or economic barrier to U.S. decarbonization. Most investments in the green economy eventually pay for themselves, and the modest costs to some sectors of the economy are more than offset by the wider benefits for society. For example, investing in solar or wind energy is typically more cost-effective than investing in coal generation, even without considering the added benefits of reductions in pollution.
If the targets themselves were themselves not the problem, what went wrong? The answer, perhaps not surprisingly, is Congress. Attempts to advance climate legislation to support emissions promises have frequently run aground in the Senate, where Republicans, often supported by Democrats in coal regions, blocked climate legislation. Our analysis suggests that partisanship, Senate rules, and the power of vested interests have combined to make progress all but impossible
Because overshooting emissions targets comes with real, measurable economic consequences, citizens and civil society organizations are advancing lawsuits against federal and state governments, as well as against private corporations. The most prominent of these is Juliana v. United States, in which a group of young plaintiffs allege that the U.S. government’s inaction on curbing greenhouse gas emissions has violated, among other things, their constitutional rights to life, liberty, and property. Whatever the eventual finding, in the short term, a political solution may offer better prospects for addressing climate change than a legal one, but that could change.
In many climate cases, it has historically been difficult to prove causation—that emissions from one particular source caused specific environmental damage or personal harm. But that is starting to change.
For one, recent advances in climate science make it possible to link the damage associated with an extreme weather event to emissions from an individual country. For example, in a recent study in Nature, the authors use the heat wave that broiled Argentina in 2013 and 2014 as a case study. They credibly find that emissions from the the United States made the heat wave 28-34 percent more likely.
Meanwhile, a slew of lawsuits around the world last year have started to establish legal precedent. In a 2015 Dutch case, the court ruled that the government of the Netherlands had failed to live up to its duty to protect its citizens and ordered it to limit greenhouse gas emissions to 25 percent below 1990 levels by 2020. The finding was upheld in 2018 and has sparked several similar cases, including in the United Kingdom, Ireland, and Belgium.
Better science and an increasing amount of climate litigation, including in the United States, will put pressure on the U.S. legal system to start finding answers to the constitutional, human rights, and environmental questions arising from climate change. Focusing on excess emissions could help litigants in their quest to nail down causation in climate cases, as historical emissions and emissions under set targets are morally difficult to adjudicate.
With every year that passes, climate change is more devastating. A large and growing majority of Americans want the U.S. government to do its part to limit the damage. Three decades of climate history suggests that there will be another opportunity for legislation—be it a Green New Deal or something else. If not, the prospect of litigation looms large: Someone, somewhere, at some time, will eventually have to pay the price for America’s emissions.